pub fn new_birthday_probability(n: u32) -> f64 {
    if n < 2 {
        return 0.0;
    }

    let days_in_year = 365.0;
    let mut probability = 1.0;

    for i in 0..n {
        probability *= (days_in_year - i as f64) / days_in_year;
    }

    let result = 1.0 - probability;

    (result * 10000.0).round() / 10000.0
}
